1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io.comparator;
18
19 import java.io.File;
20 import java.io.Serializable;
21 import java.util.Comparator;
22
23 /**
24 * Compares two files using the <b>default</b> {@link File#compareTo(File)} method.
25 * <p>
26 * This comparator can be used to sort lists or arrays of files
27 * by using the default file comparison.
28 * </p>
29 * <p>
30 * Example of sorting a list of files using the
31 * {@link #DEFAULT_COMPARATOR} singleton instance:
32 * </p>
33 * <pre>
34 * List<File> list = ...
35 * ((AbstractFileComparator) DefaultFileComparator.DEFAULT_COMPARATOR).sort(list);
36 * </pre>
37 * <p>
38 * Example of doing a <i>reverse</i> sort of an array of files using the
39 * {@link #DEFAULT_REVERSE} singleton instance:
40 * </p>
41 * <pre>
42 * File[] array = ...
43 * ((AbstractFileComparator) DefaultFileComparator.DEFAULT_REVERSE).sort(array);
44 * </pre>
45 * <h2>Deprecating Serialization</h2>
46 * <p>
47 * <em>Serialization is deprecated and will be removed in 3.0.</em>
48 * </p>
49 *
50 * @since 1.4
51 */
52 public class DefaultFileComparator extends AbstractFileComparator implements Serializable {
53
54 private static final long serialVersionUID = 3260141861365313518L;
55
56 /** Singleton default comparator instance */
57 public static final Comparator<File> DEFAULT_COMPARATOR = new DefaultFileComparator();
58
59 /** Singleton reverse default comparator instance */
60 public static final Comparator<File> DEFAULT_REVERSE = new ReverseFileComparator(DEFAULT_COMPARATOR);
61
62 /**
63 * Constructs a new instance.
64 */
65 public DefaultFileComparator() {
66 // empty
67 }
68
69 /**
70 * Compares the two files using the {@link File#compareTo(File)} method.
71 *
72 * @param file1 The first file to compare
73 * @param file2 The second file to compare
74 * @return the result of calling file1's
75 * {@link File#compareTo(File)} with file2 as the parameter.
76 */
77 @Override
78 public int compare(final File file1, final File file2) {
79 return file1.compareTo(file2);
80 }
81 }